To schedule radio resources in an efficient manner, a network equipment needs to obtain adequate and accurate downlink channel state information, which mainly includes signal-interference-noise ratio (SINR, signal-interference-noise ratio) information on all frequency bands. To obtain the SINR information, a current LTE R8 specifies that the SINR information should be measured and reported by a user equipment (UE).
The process of measuring and reporting the SINR information mainly includes: The network equipment sends a certain reference signal used for measuring a downlink channel to a UE in a coverage area; after receiving the downlink reference signal, the UE obtains downlink channel state information (CSI, channel state information) through measurement and calculation; the UE calculates downlink SINR on all the frequency bands according to measured channel response and interference information, quantizes the measured downlink SINR into a channel quality indication (CQI, Channel Quality Indication) according to a certain rule, and feeds back the CQI to the network equipment.
During the implementation of the present invention, the inventor discovers that the network equipment mainly schedules radio resources according to the CQI fed back by the UE. Therefore, whether the feedback information is correct directly decides the accuracy and efficiency of the scheduling. From one aspect, because the downlink SINR varies with the time domain and frequency domain, the SINR needs to be cut into multiple sub-bands in the frequency domain, and the CQIs of multiple sub-bands need to be fed back in order to obtain an accurate CQI. In addition, to trace time change features of the SINR, the UE needs to feed back the CQI periodically. Therefore, uplink overheads are increased.